Yesterday we established that anti-access is neither novel nor especially radical. It is a method the weak use to overcome the strong when the strong venture onto their home ground. Coastal defenders can hope to win despite their overall inferiority. Or they can hope to prevail without fighting, persuading stronger yet far away powers that the costs of operating offshore exceed the payoffs from doing so. If so, they can dissuade adversaries from making the attempt. They win by convincing prospective antagonists to keep their distance.

Iran, like China, wants to keep U.S. forces at bay. Can it do so? Before undertaking warlike competition, Clausewitz urges strategists to survey each belligerent’s political stakes, its strength and situation, and the capacity of its government and people, as well as the likely sympathies and actions of third parties. A quick survey of these factors illuminates the differences between Iranian and Chinese anti-access strategy. Leave aside the glaring disparities between the two coastal states’ populations, economic capacity, and other indices of material strength. The Islamic Republic clearly cannot field the imposing array of anti-access weaponry China does.

But Tehran’s capacity for mischief-making remains considerable. Look at the map. As it gazes eastward across the Pacific Ocean, China’s People’s Liberation Army Navy must defend a broad, distended front—namely the China seas—against oncoming U.S. forces and America’s Asian allies. U.S. forces must approach the Persian Gulf along a narrow front. They must traverse the very predictable route through the focal point at Hormuz. The Iranian military, accordingly, can simplify its anti-access problem by closing the Strait of Hormuz. If Iranian commanders deploy their limited military capabilities adroitly, they can threaten to pummel U.S. naval forces trapped within the Persian Gulf while holding U.S. reinforcements at risk outside the Gulf, along the Gulf of Oman approaches to Iran’s coasts.

Am I predicting that Tehran can render the Strait permanently impassable? No. But think about the politics, rather than the hardware and tactics, of access denial. Clausewitz observes that you can win wars in three ways: disarm your enemy, rendering him powerless to resist your demands; show him he’s unlikely to win; or convince him the costs of winning will be exorbitant, far beyond the value he places on his political stakes. Defeating the U.S. military outright probably lies beyond Iranian capacity, but Clausewitz’s other options remain open to Tehran.

Tehran, that is, can put Washington on notice that it will pay a high if not unacceptable price for access to the Gulf region. A U.S. president might hesitate before making a decision of this gravity in times of strife; he might modify U.S. deployment patterns, forcing U.S. airmen and seamen to fight inside the Persian Gulf from aircraft carriers and land bases outside the Strait of Hormuz; he might abjure the effort altogether. Tehran would either prevail or, more likely, gain time to accomplish its goals. That could be a win from the Iranian standpoint. Americans must not assume the mismatch between U.S. and Iranian military capabilities guarantees automatic victory in the Gulf.

This barely scratches the surface of a large topic. But examining the geospatial aspects of strategy is always a good way to begin parsing such topics. In my next post we’ll survey how North Korea approaches the anti-access question.